Submission #864538

#	Time	Username	Problem	Language	Result	Execution time	Memory
864538		serifefedartar	Zagrade (COI17_zagrade)	C++17	100 / 100	776 ms	50388 KiB

zagrade

#include <bits/stdc++.h>
using namespace std;
 
#define fast ios::sync_with_stdio(0);cin.tie(0);
#define s second
#define f first
typedef long long ll;
const ll MOD = 1e9 + 7;
const ll LOGN = 20; 
const ll MAXN = 3e5 + 100;

vector<vector<int>> graph;
int marked[MAXN], sz[MAXN], ch[MAXN];
map<int,int> cnt;
ll ans = 0;
int get_sz(int node, int parent) {
	sz[node] = 1;
	for (auto u : graph[node]) {
		if (u == parent || marked[u])
			continue;
		sz[node] += get_sz(u, node);
	}
	return sz[node];
}

int find_centro(int node, int parent, int n) {
	for (auto u : graph[node]) {
		if (u != parent && !marked[u] && sz[u] * 2 >= n)
			return find_centro(u, node, n);
	}
	return node;
}

void dfs(int node, int parent, int sum, int mx, int mn) {
	sum += ch[node];
	mx = max(mx, sum);
	mn = min(mn, sum);

	/*
		( ) ) ) (
		1 0 -1 -2 -1
		sum != mn olduğunda sağlamıyor.
	*/

	if (sum == mn)
		ans += cnt[-mn];

	for (auto u : graph[node]) {
		if (u == parent || marked[u])
			continue;
		dfs(u, node, sum, mx, mn);
	}
}

void add(int node, int parent, int sum, int mx, int mn) {
	sum += ch[node];
	mx = max(mx, sum);
	mn = min(mn, sum);

	if (sum == mx)
		cnt[sum]++; 

	/*
		( ) ) ) ( (
		1 0 -1 -2 -1 0
		sum = 0
		mx = 1
	*/

	for (auto u : graph[node]) {
		if (u == parent || marked[u])
			continue;
		add(u, node, sum, mx, mn);
	}
}

void solve(int node) {
	int n = get_sz(node, node);
	int centro = find_centro(node, node, n);

	cnt.clear();
	marked[centro] = true;
	if (ch[centro] == 1)
		cnt[1]++;

	for (auto u : graph[centro]) {
		if (marked[u])
			continue;
		dfs(u, centro, 0, 0, 0);
		add(u, centro, ch[centro], max(0, ch[centro]), min(0, ch[centro]));
	}

	ans += cnt[0];

	cnt.clear();
	reverse(graph[centro].begin(), graph[centro].end());
	for (auto u : graph[centro]) {
		if (marked[u])
			continue;
		dfs(u, centro, 0, 0, 0);
		add(u, centro, ch[centro], max(0, ch[centro]), min(0, ch[centro]));
	}

	for (auto u : graph[centro]) {
		if (!marked[u])
			solve(u);
	}
}

int main() {
	fast
	int n, a, b;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		char c; cin >> c;
		ch[i] = (c == '(' ? 1 : -1);
	}

	graph = vector<vector<int>>(n+1, vector<int>());
	for (int i = 1; i < n; i++) {
		cin >> a >> b;
		graph[a].push_back(b);
		graph[b].push_back(a);
	}
	solve(1);
	cout << ans << "\n";
}

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60